1. Field of the Invention
The present invention specifically relates to a projection apparatus favorable for a projector fixed on a ceiling or the like, ceiling hanging hardware for the projection apparatus, and a method of controlling operation of the projection apparatus.
2. Description of the Related Art
There is proposed a ceiling-hanging type liquid crystal projector that is capable of finely adjusting the position of a projection area for projecting a video image onto a screen, while the projector is hanging. Such a projector is disclosed in, for example, Jpn. Pat. Appln. KOKAI Publication No. 9-166964.
The following method including the technique of the above Publication is widely executed particularly among audio/video fans. They have a movie theater in their home and fix a projector on the ceiling of the theater by ceiling hanging hardware to project a video image onto a large-sized screen.
The temperature of an area close to the ceiling is generally the highest, and the projector itself includes a lamp such as a high-pressure mercury lamp, which generates a very high heat, as a light source. It is thus essential to cool the projector positively. The area close to the ceiling is by no means good environment for the projector, which is very likely to break the expensive lamp.
In order to resolve the above drawback, air can be circulated in the room by the use of an elevated electric fan, an air circulator or a ceiling fan. However, these devices blow air at a distance from the projector and their mechanisms are complicated. As compared with the complicated mechanisms, the devices seem to produce little cooling effect on the projector. A user has to judge the conditions of the projector at any time and operate the devices appropriately. The user's burden increases accordingly.